title: Human megakaryocytes. II. Expression of platelet proteins in early marrow megakaryocytes.
abstract: Analysis of various platelet proteins by immunofluorescence demonstrated that platelet glycoproteins Ib, IIb, and IIIa, as well as plasma factor VIII antigen (factor VIII:AGN), platelet factor 4, and fibronectin are present in the vast majority of morphologically recognizable megakaryocytes. In addition, a small number of lymphoid-like mononuclear marrow cells, representing approximately 1.4--2.9/10(4) marrow cells, was found to express the same platelet proteins. This population of early marrow megakaryocytes is analogous to small acetylcholinesterase-positive rat and mouse marrow cells. Fc receptors for IgG were expressed in all megakaryocytes and megakaryocyte precursors, whereas the Ia antigen was detected only on a proportion of mature megakaryocytes and not on only early or precursor megakaryocytes. Platelet glycoproteins Ib, IIb, and IIIa, as well as factor VIII:AGN, and platelet factor 4 were established as distinct markers for marrow megakaryocytes and may be helpful for identifying megakaryocytic cells as well as for monitoring events of megakaryocyte differentiation.
mesh_terms: D000941:Antigens; D001792:Blood Platelets / Q000502:physiology*; D001798:Blood Proteins; D001854:Bone Marrow Cells; D005169:Factor VIII / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006801:Humans; D008533:Megakaryocytes / Q000166:cytology / Q000502:physiology*; D010978:Platelet Factor 4; D011961:Receptors, Fc / Q000276:immunology; D013997:Time Factors
chemical_list: D000941:Antigens; D001798:Blood Proteins; D011961:Receptors, Fc; D010978:Platelet Factor 4; D005169:Factor VIII